1. Technical Field
The present invention relates to an earphone structure, and more particularly, to a waterproof earphone structure capable of resisting water, avoiding sound distortion, and balancing the pressure, temperature and humidity inside/outside an auditory canal.
2. Description of Related Art
All liquids (wherein water is also a liquid) have surface tension which is formed by the cohesion of liquid molecules. In a liquid, each molecule is attracted or repelled by adjacent molecules in all directions, so that the resultant force of the molecular forces exerted on the molecules inside the liquid is substantially zero.
However, the attraction and repulsion exerted on the liquid molecules at a liquid-gas interface in all directions are unbalanced, so that the molecules at the surface layer of the liquid are attracted towards the inside of the liquid, and some of the molecules at the surface layer are pulled towards the inside of the liquid, and the surface area of the liquid is reduced, and such phenomenon is called surface tension.
With reference to FIG. 10 for the relationship between surface tension and tube diameter, the smaller the tube diameter, the greater the surface tension. Ends of a first tube 410, a second tube 420, and a third tube 430 arranged in an ascending orders of tube diameters are sequentially filled with a liquid 300. As the tube diameter increases, the surface tension decreases, so that a greater quantity of liquid 300 enters into the tube.
In general, an earplug of earphones or hearing aids generally does not have a waterproof function, and the conventional earphones or hearing aids may be damaged easily when they are soaked or splashed with liquid or water. Even worse, the liquid or water may enter into a user's ear and cause discomfort or injury to the user's ear.
In view of the aforementioned problem, it is an important subject for designers and developers of the related industry to design and develop an earphone structure capable of resisting water by the principle of surface tension, and such earphone structure not just resists water or liquid only, but also maintains original sound quality, balances the pressure, humidity and temperature inside/outside an auditory canal, and provides a comfortable and ergonomic earphone or earplug.